• The term R is used to refer to both the programming language and the software that interprets the scripts written using it.
• RStudio is an interactive development environment which as this defintion suggests assists us in using R

To understand computations in R, two slogans are helpful:

• Everything that exists is an object.
• Everything that happens is a function call.

— John Chambers

“Reproducibility involves being able to recalculate the exact numbers in a data analysis using the code and raw data provided by the analyst…Reproducibility should not be confused with “correctness” of a data analysis. A data analysis can be fully reproducible and recreate all numbers in an analysis and still be misleading or incorrect."

Jeff Leek, The Elements of Data Analytic Style

The working directory. This is where R looks for files that you ask it to load

1. Machine readable (no white space, punctuation, upper AND lower-case…)
2. Human readable (makes sense in 6 months or 2 years time)
3. Plays well with default ordering (numerical or date order)

• Google: ‘Typically adding “R” to a query is enough to restrict it to relevant results’. Hadley Wickham
• Check out the help pages using ?function_name e.g. ?mean
• Join RStudio Community
• Learn how to make a reproducible example

# Make a character vector using the combine function, c()
cards <- c("ace", "king", "queen", "jack", "ten")

# Return the values of cards
cards

## [1] "ace"   "king"  "queen" "jack"  "ten"

# Return the third value of cards
# Indexing starts at 1
cards[3]

## [1] "queen"

# Make a character vector using the combine function, c()
cards <- c("ace", "king", "queen", "jack", "ten")
# Make a numeric vector using seq()
my_sequence <- seq(1:7)

# Check the type of each vector
typeof(cards)

## [1] "character"

typeof(my_sequence)

## [1] "integer"

1. Each variable forms a column
2. Each observation forms a row
3. Each cell contains a single value